The present invention relates to water filtration systems and, in particular, to a replaceable water filter cartridge for use in a variety of water filtration systems. The water filter cartridge is described as part of a water filtration system for purifying drinking water, but the invention is not restricted to such an application.
Many water filtration systems utilize a water filter cartridge having multiple stages of filtration that is capable of being replaced after the filtering media contained therein have been expended. This allows continued use of the original water filtration system by simply replacing the expended cartridge with a new cartridge.
A problem with such water filtration systems is that not all of the filtration stages of the water filter cartridge are expended at the same rate. More specifically, the effectiveness of the initial filter or pre-filter of such water filter cartridges tends to diminish well before the effectiveness of the commonly used bactericidal resin stage. The entire water filter cartridge must be disposed of when the pre-filter is no longer effective, resulting in the waste of still usable elements of the water filter cartridge.